Trigger an event or notification upon the output of a command.
triggerd is a sysadmin/automation tool used to trigger an event or notification upon the output of a command.
An event file containing the trigger criteria is created. Ideally, you’ll create a cron entry or systemd timer to execute triggerd EVENTFOLDER at a regular interval. If the command status or output matches the trigger criteria, a trigger event or notification is executed and the event file is marked triggered.
triggerd is perfect for querying a webpage for matching text or anything of the sort. I originally created it for use with a modified version of urlwatch to notify me upon certain changes to webpages, however the potential uses are limitless.
The script was originally written as a Bash shell script before it was rewritten in Python. The Bash version is nearly identical and is a great alternative if Python 3 is not available in your environment. It is included in this repository under scripts/triggerd.sh.
The easiest way to install triggerd is via pip:
pip3 install --user triggerd
FYI: The shell version of triggerd will be installed to your local bin folder as triggerd.sh
Run the following command to update to the most recent version:
pip3 install --upgrade --user triggerd
triggerd is controlled via configuration files called event files. You can execute it as follows:
triggerd FILE1 FILE2 FILE3...
Or against entire directories of event files:
triggerd EVENTFOLDER1 EVENTFOLDER2...
You can test your event file configuration without actually executing it:
triggerd --verify FILE
The –verbose option can be used to display execution details:
triggerd --verbose FILE
Please note: Event files are parsed manually, they are not ‘sourced’ by the shell. Contents are executed by the shell exactly as they appear.
Basic documentation (sample event file and trigger template file) is installed to $PREFIX/share/triggerd/examples
Here is a sample event file that triggers when google.com is not accessible via curl:
COMMAND=curl -sL google.com EVENT_NAME=Google Availability MATCH_CONTENT=0 MATCH_CRITERIA=ne STATUS=enabled TEST_TYPE=status TRIGGER_CUSTOM=notify-send --urgency=critical "$EVENT_NAME" "Google is not available!"
Here is a sample event file that triggers when the google.com homepage source code contains the word surprise:
COMMAND=curl -sL google.com EVENT_NAME=Google Surprise MATCH_CONTENT=surprise MATCH_CRITERIA=contains STATUS=enabled TEST_TYPE=content TRIGGER_CUSTOM=notify-send --urgency=critical "$EVENT_NAME" "Google contains a surprise!"
Here is a sample event file that triggers when /tmp is greater than or equal to 10M in size:
COMMAND=du -ms /tmp | cut -f1 EVENT_NAME=Size Check MATCH_CONTENT=10 MATCH_CRITERIA=ge STATUS=enabled TEST_TYPE=arithmetic TRIGGER_CUSTOM=notify-send --urgency=critical "$EVENT_NAME" "/tmp is >= 10M in size!"
arithmetic content status # exit code
MATCH_CRITERIA for arithmetic and status tests:
eq ge gt le lt ne
MATCH_CRITERIA for content tests:
contains does_not_contain matches does_not_match null not_null
STATUS indicates whether the event is active:
enabled disabled triggered # this will be set by triggerd upon a trigger event
There are two types of triggers available.
TRIGGER_CUSTOM is used to indicate a shell command.
i.e. TRIGGER_CUSTOM=notify-send "Trigger Notification"
TRIGGER_NAMED is used to indicate the name of a trigger template.
The trigger templates may be defined in $HOME/.config/triggerd/triggers.conf
ie. special=notify-send --icon=~/.config/triggerd/icons/special.png --urgency=critical "triggerd: $EVENT_NAME" "special event was triggered!"
The event name can be referenced in either trigger as $EVENT_NAME. The same goes for $MATCH_CONTENT.
If no trigger is indicated, a default notification will be displayed via notify-send.
Copyright (c) 2015 Six (firstname.lastname@example.org).
Licensed under the GPLv3 license.
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